JPH09503821A

JPH09503821A - Method for adjusting composition of liquid metal such as steel and apparatus for implementing the same

Info

Publication number: JPH09503821A
Application number: JP7511389A
Authority: JP
Inventors: アレックスミシャル，ジャン; ガイ，アンリ; ロス，ジャン−リュク
Original assignee: ソラックソシエテアノニム
Priority date: 1993-10-15
Filing date: 1994-10-05
Publication date: 1997-04-15
Also published as: ATE157573T1; WO1995010377A1; KR100327288B1; DE69405401D1; EP0723487B1; ES2107252T3; EP0723487A1; US5868816A; FR2711083B1; CA2174109A1; AU683094B2; AU7858294A; DE69405401T2; FR2711083A1; KR960704659A

Abstract

PCT No. PCT/FR94/01161 Sec. 371 Date May 20, 1996 Sec. 102(e) Date May 20, 1996 PCT Filed Oct. 5, 1994 PCT Pub. No. WO95/10377 PCT Pub. Date Apr. 20, 1995A process for adjusting the composition of a liquid metal, such as steel, is provided wherein liquid metal is sucked up from a start receptacle into a reactor which is at a reduced pressure with respect to the start receptacle. First, the liquid metal is made to flow inside the reactor under conditions close to plug flow where it undergoes a metallurgical treatment. Next, after the liquid metal has been conveyed through the reactor it is completely discharged into a finish receptacle which is also at a reduced pressure with respect to the reactor. To insure thorough mixing, the reactor is divided into a plurality of cells, each of which has its own independent gas injector for agitating the liquid metal therein.

Description

【発明の詳細な説明】鋼などの液体金属の組成の調節方法と、それを実施するための装置本発明は液体鋼の製錬に関するものであり、特に炭素含有率が極めて低く、当然窒素および酸素の含有率も低い高純度な鋼の製錬に関するものである。現在の液体金属の製錬では「ＲＨ」とよばれる形式の真空リアクタを用いるのが一般的である。このリアクタは下記1)および2)を備えている： 1) 内側が耐火物でライニングされたほぼ円筒形の深い容器（その上部はリアクタの動作中に容器内部を少なくとも１torrに減圧可能なガス吸引装置に接続されている） 2) 内側および外側が耐火物でライニングされた断面が円筒形または楕円形の２本のパイプすなわち浸漬管（一端は上記容器の底部で開口しており、一本の浸漬管にはガス（通常はアルゴンガス）を吹込む装置を備えている）このリアクタはは以下のように使用される。すなわち、処理すべき液体金属を収容した取鍋をＲＨの下に運び、浸漬管の下端を取鍋中に浸漬する。その後、容器内を減圧する。それによって容器内の一定量の金属が吸上げられる。最後に一方の浸漬管中へのガスの吹込みを開始する。この吹込みの機能は浸漬管中にある金属を容器の方へ移動させることである。従って、この浸漬管は「上昇浸漬管」とよばれる。容器内を通った金属は次いで「下降浸漬管」とよばれる他方の浸漬管を介して再び取鍋へ下降する。こうして取鍋と容器との間を金属が連続して循環する。処理時間（一般には10〜30分間）中、金属の液滴は複数回容器内で滞留する。その平均滞留時間は浸漬管内での金属の流速と、取鍋と容器との容量比とで決まる。減圧下の容器内に液体金属を移動させることによって原理的には液体金属中に溶解している水素と液体金属中に溶解している窒素（水素ほど低下はできない）との含有率を下げることができる。容器内で起こる他の冶金操作には下記のものがある： 1) 予め金属中に溶解している酸素または容器の壁面に挿入したランスまたは羽口を介して意図的に吹込む酸素と炭素を結合させる部分的脱炭、 2) 空気および取鍋のスラグから遮断された状態すなわち最適効率で行われる合金元素の添加、 3) アルミノテルミーによる金属の再加熱（金属にアルミニウムを添加した後酸素を吹込むことによるアルミニウムの酸化による再加熱）また、取鍋と容器との間を金属が循環することによって取鍋内の金属が緩やかに撹拌される。これは非金属の介在物を沈澱させる上で好都合である。鋼を用いる産業では、炭素含有率が極めて低い(50ppm以下)の鉄製品、特に延性および引張強度に優れた冷間圧延シート、深絞り加工用鋼およびクロム−モリブデンフェライトステンレス鋼等に対する要求が高まっている。こうした鋼を工業的規模で製造するのに最も適したイン−ラドル式の冶金リアクタはＲＨであることが明らかになってきた。事実、リアクタ内での脱炭反応速度は上昇浸漬管中あるいは容器内へ多量のガスを注入することによって良くなる。すなわち、300 ｔの液体鋼を収容した取鍋の場合、容量が15ｔのＲＨ容器を用い、流速を240t／分とし、反応時間を10分にすると、鋼の炭素含有率を300ppmから20ppmに低下させることができる。高純度鋼に対する需要は益々高くなるので、さらに炭素含有率の低い（５〜10 ppm）鋼を、少なくとも現状の設備と同等な生産性（大型総合工場で約10ｔ／分）で通常的に生産し得ることが極めて近い将来に要求されるであろう。しかし、現在のＲＨでは液体鋼中の平均炭素含有率が30ppm以下になると脱炭反応速度が明らかに低下する。反応速度を上げれば他の製鋼設備の最適運転状態に合った時間で所望の冶金性能を達成し得るが、そうするには金属の流量と吹込むガス量とを大幅に増加するしかない。しかし、そうすると耐火物が短時間で磨耗するため、プラントの運転をより頻繁に停止しなければならず、プラント運転の信頼性が低下する。簡単にいえば、技術的および経済的に十分な条件下で、工業的速度で実質的に 10ppm以下の炭素含有率を達成することは従来設計のＲＨでは無理であると思われる。いずれにせよ、液体鋼中の炭素含有率をできるだけ低くすることは重要である。事実、鋼はその後の製造工程および鋳造工程で加炭される機会が多い（例えば、タンディッシュや鋳型の耐火物、表面被覆粉末等との接触で加炭される）。本発明の目的は、十分な生産効率の条件下で液体鋼中の炭素含有率を10ppm以下に近づけるための新規な冶金リアクタを提供することにある。本発明のリアクタは脱炭の程度は低いが酸化介在物の含有率が極めて低い鋼を製造する場合にも使用することができる。本発明の対象は、液体金属を開始槽からこの開始槽に対して減圧されたリアクタ内に吸引し、リアクタ内で金属をプラグフローに近い条件で流し、金属を冶金処理し、リアクタを通過した金属を最終槽に排出し、この最終槽に対してもリアクタが減圧になっていることを特徴とする液体金属の組成の調節方法にある。開始槽に金属を連続的に供給し、最終槽から金属を連続的に流出させるのが好ましい。本発明方法の１実施例では液体金属は鋼であり、冶金処理は脱炭、脱窒素または炭素を用いた減圧脱酸素を含み、最終槽は連続鋳造用のタンディッシュである。本発明の他の対象は、液体金属を収容する開始槽と、リアクタと、終了槽とを有し、リアクタは容器を備え、この容器はその内部を開始槽および終了槽内の圧力に対して減圧状態に維持する手段と、一端が開始槽に収容された液体金属中に浸漬され、他端が容器の底部に接続された上昇浸漬管とよばれる第１の浸漬管と、一端が最終槽に収容された液体金属中に浸漬され、他端が容器の底部に接続された下降浸漬管とよばれる第２の浸漬管と、液体金属を各浸漬管とリアクタの容器とを介して開始槽と最終槽との間で連続的に流す手段とを備えており、容器は液体金属が各浸漬管間を移動する際に液体金属をプラグタイプのフローに近い状態で流すような形状をしていることを特徴とする鋼などの液体金属の組成を調節するための設備にある。本発明の設備は下記のものを含む液体鋼の組成を調節するためのプラントに組み込まれる： 1) 液体鋼の一次製錬装置、 2) 液体鋼を一次製錬装置から液体金属中に脱酸素剤を導入する手段と混合手段とを備えた第１槽へ連続的に注ぐ手段、 3) 内部を減圧する手段と、第１槽に収容された液体金属）中に浸漬された第１の浸漬管と、中間槽中に浸漬された第２の浸漬管とを有する容器を含む、液体金属を大まかに脱炭するためのリアクタ、 4) 容器に設けられた液体金属中に酸素を吹込む手段、 5) 液体金属を第１槽と中間槽との間で連続的に流す手段、 6) 少なくとも１つの上記の液体金属の組成を調節するため設備（中間槽はこの設備では開始槽を構成する）。以下の説明から理解できるように、本発明の新規なリアクタはＲＨと共通点を有する。すわなち、減圧容器と２本の浸漬管が存在し、各浸漬管を介して金属が容器に侵入し、容器から出る。しかし、取鍋とリアクタとの間で連続的に液体金属を循環するという原理は採用していない。すなわち、本発明ではリアクタを出た金属は開始槽以外の槽へ注入され、同じリアクタへは戻らない。さらに、ＲＨが完全に混合リアクタとして挙動するのに対し、本発明のリアクタ内の液体鋼はプラグフローに近いフローを行わなければならない。以下の説明で明らかなように、必要に応じてリアクタを完全に混合された複数のセルに分割することによって、擬似プラグフローが得られ、各セル間の物質交換は最小限に抑えられる。本発明リアクタは連続的または半連続的な液体鋼製造ラインに組み込むのが有利である。本発明は添付図面を参照した以下の説明からより明瞭に理解できよう。図１は本発明の冶金リアクタの一実施例の概念的長手方向断面図。図２は本発明のリアクタが組み込まれた超低炭素鋼の製造・鋳造ライン全体の一実施例の概念的長手方向断面図。ＲＨで超高度な脱炭を十分な早さで行うことができない理由の１つは、液体金属の所定単位部分が相対的に短い平均時間でしか減圧に曝されないためと考えられる。前記の例でいえば、300ｔの取鍋と組み合わされた液体金属容量が15ｔで、流量が240ｔ／分のＲＨでは、金属の一部がＲＨ容器内に留まる平均滞留時間は10分間の処理に対してわずか30秒である。この30秒の大部分は炭素含有率を20 0〜400ppmから30ppmにする比較的容易な脱炭の最初の段階にとられてしまい、その後には、他の製鋼設備（転炉、電気炉、連続鋳造）に匹敵するような製造速度で10ppmレベル以下までに脱炭するのに必要な十分な時間は残されていない。さらに、取鍋と容器との間で金属を連続的に再循環させる原理であるので、容器に供給される金属は既に容器内にあって脱炭を受けている金属よりも常に脱炭度が低い。容器は完全に混合されたリアクタとして稼働するので、容器内にある金属の任意の瞬間での平均炭素含有率Ｃ_Vと取鍋内にある金属の平均炭素含有率Ｃ_Lとは定義できる。Ｃ_Lは常にＣ_Vよりも大きいので、炭素含有率Ｃ_Lを有する脱炭度の低い金属の流入によってＣ_Vの低下が遅くなるということが分かる。このことは反応速度の効率を表すためのＣ_V／Ｃ_L比を含む脱炭の数学モデルによってよく表せる。脱炭を速く行うためにはＣ_V／Ｃ_L比をできるだけ１に近づけなければならない。従来のＲＨではこの値は平均で0.6程度であり、脱炭の進歩段階と金属の再循環速度との関数である。このＣ_V／Ｃ_Lの条件は、処理すべき金属が全て同時に減圧に曝された場合に理想的に満足され、これは従来設備で取鍋内を減圧した場合に相当する。しかし、そのような設備を用いた場合には、ガスを金属全体に加えることになるため、ＲＨの基本的利点の１つである金属中に多量のガスを通過させて脱炭反応速度を速くするという利点が失われる。すなわち、単純に減圧した取鍋にそのように多量のガスを通すと、金属の飛沫が過剰に発生して設備が著しく急速に損傷する。減圧した取鍋を用いた場合にはＲＨのもう１つの利点すなわち減圧に曝される金属の表面が容器内に含まれる体積よりも大きくなるという利点も無くなる。従って、単純に減圧した取鍋または減圧炉−取鍋では全体として脱炭を十分に速くできないため、炭素含有率を40ppm以下にするために工業的に用いることはできない。Ｃ_V／Ｃ_Lの理想的条件に近づくためのもう１つの方法は、浸漬管の形状と上昇浸漬管に吹込むガスの流量とを変えて取鍋と容器との間の金属の循環速度を上げることであるが、そうすると耐火物の磨耗が著しく加速する。図１は本発明の単位リアクタの原理と、それを鋼の連続製造設備に組み込んだ時の実施例の概念図である。この鋼製造設備は図示していない冶金容器、例えば製鋼取鍋や転炉、電気炉に似た金属の一次製錬設備から制御可能な流量で連続的に流入する液体鋼２の供給樋１を備えている。一次製錬設備も連続的に運転される。供給樋１は覆い３に連結され、覆い３は大気圧下にある中間槽４に支持され、液体鋼２がこの中間槽４中に流入する。不活性ガス、例えばアルゴンが供給樋１の内部と覆い３の下側に注入されて金属２を空気から保護するのが好ましい。液体鋼２からはその内部に溶解しているガス（水素と窒素）と炭素を可能な限り除去することが望まれる。そのために本発明の冶金リアクタ５を使用する。従来のＲＨ型リアクタと同様に、本発明のリアクタ５も内側が耐火物でライニングされており、下記のものを備えている： 1) ある瞬間に流入する液体鋼２を所定量だけ収容するための容器６（この容器６はＲＨ容器と同様に液体金属の飛沫によって過剰な損傷を受けないようにその上部が十分に高くなっていなければならない） 2) 容器６内を減圧するためのガス吸引装置７ 3) 覆い３を貫通し、中間槽４中に浸漬された上昇浸漬管８（容器６内を通して液体金属２を流し、その流れを助けるためのアルゴン等のガスを注入する手段９を備えていてもよい） 4) 容器６から出た液体金属が通る下降浸漬管10。本発明では、ＲＨとは違って、下降浸漬管10は上昇浸漬管８と同じ槽に液体金属を戻すのではなく仕上げ槽11へ液体金属を放出する。図示した実施例では仕上げ槽11は連続鋳造設備用のタンディッシュである。このタンディッシュ11は必要に応じて少なくとも１つの出口ノズル12を備え、液体金属２がこの出口ノズル12 を介して、図示していないストッパーロッドまたはスライド弁によって制御可能な流量で、壁面内側が強制冷却された底のない鋳型13へ連続的に流入し、鋳型13 内では鋼の表皮14が凝固を開始し、この表皮は鋳型13の形状・寸法に応じてスラブ、ブルーム、ビレット等の冶金製品15になる。ＲＨ容器はほぼ円筒形で、その内径は最大で数メートルである。この構造からＲＨは完全に混合型リアクタの特性を有している。これに対して、本発明の容器６はプラグフロー型リアクタにできるだけ近い特性を有するリアクタ５でなければならない。プラグフロー型リアクタでは脱気および／または所定レベルまで脱炭された鋼はそれより純度の低い鋼と混ざり合うことはない。そうするための１つの解決法は容器６の内部をダクト型にして、断面が矩形またはほぼ矩形の細長い通路にし、その端部に浸漬管８、10を連結することである。浸漬管８と10との間の距離と通路の幅との比は少なくとも６にする。例えば容器６の幅を１〜1.5ｍとし、浸漬管８と10との間の距離を８〜10ｍにすることができる。脱炭・脱気効率は、減圧に曝された液体金属２の表面積と容器５内にある液体金属２の体積との比に大きく依存する。この比はできるだけ高くなければならない。すなわち、同じ容積の場合、容器５中の金属の深さ「ｅ」は深過ぎてはならないということを意味する（例えば0.40〜0.80ｍにする）。この深さはプラント全体の構造（特に容器６と中間槽４およびタンディッシュ11との高さの差）と、容器６の内部の液体鋼２の表面16に加わる圧力と中間槽４およびタンディッシュ 11の内部での液体鋼２の表面17に加わる圧力、大気圧との間の圧力差ΔＰとによって支配される。リアクタの容器６内の液体鋼２の表面と、大気圧に曝されている表面16および 17との間の高さの平均的差をΔｈとすると、Δｈ＝ΔＰ／ρ・ｇ〔ρは液体鋼の密度（約7000kg／m³）、ｇは重力加速度（9.8m／s²）〕となる。従って、 Δｈ（ｍ）≒1.46・10^-5ΔＰ（Pa）容器６内の絶対圧をＰとし、中間槽４とタンディッシュ11に１atmの圧力（101 325 Pa）が加わっていると仮定すると、 Δｈ≒1.46・10^-5（101325−Ｐ）従って、Ｐが50torrならばΔｈ≒1.40ｍ、Ｐが１torrならばΔｈ≒1.50ｍである。従って、容器５内の液体金属２の深さｅは、通常の圧力範囲では容器５内で得られる減圧のレベルからは相対的に独立している。上記のようにリアクタ５を介した槽４から11への金属の流れは上昇浸漬管８の所でガスを注入すれば、その一部はこのガスの注入によって支配される。しかし、いずれにせよ、この流れの存在とそれに伴う金属の流量は中間槽４内の液体金属２の表面16とタンディッシュ11内の液体金属２の表面17との間の高さの差に依存する。この高さの差は中間槽４への供給流量とタンディッシュ11を出る金属２の流量との間の差に特に関係する。リアクタ５の容器６の形状をダクトにすることは、液体金属２にプラグ型フローを行わせるのに好ましい。しかし、上昇浸漬管８からの金属の供給と、必要に応じて上昇浸漬管８内に注入されたアルゴンガスの放出と、金属の脱炭とによって（少なくともこの脱炭が最も集中的に起こっている容器６の上流領域で）、激しい撹拌が起こり、それによって流れ条件が制御不可能な程度に大きく損なわれる危険性がある。従って、リアクタ５の容器６を一連の完全混合セルに分割し、セル間での液体金属２の交換をできる限り制限して、プラグフローに近い流れを得るのが望ましい。そのためにアルゴン等の流体の注入装置19〜23を容器６の底部18に設けることができる。この注入装置は製鋼用転炉、電気炉および取鍋で用いられている例えば透過性部材または羽口等に類似したものである。これらの注入用装置19〜23はそれらが設置されている各領域で液体金属２を激しく撹拌する役目をする。注入用装置19〜23が互いに十分な間隔で隔てられていればそれらの影響が及ぶ領域は十分に離れているので、各領域間で行き来が起こることはなく、液体金属２が１つのセルから１つ前のセルに戻って拡散することはないと考えられる。従って、各セル内で均一な炭素濃度が得られ、この炭素濃度は（他の運転条件が一定である限り）経時的に一定で、この状況は数学モデルで予想される理想的脱炭条件に相当する。また、アルゴンの注入によって脱炭の反応速度が大幅に加速される。図１に示すように、容器６内にダム24〜28を設けて各セルを物理的に分離することで最適化ができる。各ダム24-28を容器６の主方向に対して直角に配置して各セル29〜34を区画し、各セルには流体注入装置19〜23を設ける（上昇浸漬管８にガスが注入される場合には１つ目のセル29の金属は上昇浸漬管８への注入で攪拌される１つ目のセル29は除くことができる）。１つ目のダム（１つ目のセル29 と２つ目のセル30とを隔てるダム）24は容器６の底18から延び、その上部は液体金属２が容器６に流入した際に溢流することが可能な敷居35となるような高さを有するのが好ましい。この構成によって流動金属２の流量を正確に制御できる。他のダム25〜28には開口36〜39が設けて各セル30〜34間に最小限の通路を確保しつつ、液体金属２が容器６内を進むことができるようにする。各開口36〜39はダム25〜28の下部に形成して、容器６が完全に排出できるようにするのが好ましい。このようにして、流体注入装置19〜23の影響が及ぶ各領域を十分に限定し、隣接した２つのセル間で金属が過剰に交換する危険を無くし、流体注入装置を多数設置することが可能になる。従って、ダムがない場合に比べて理想的プラグフローの条件により近づくことができる。ガス注入装置の代わりに、適当な方向を向いた移動電磁場を用いて金属２を攪拌する装置を用いるか、追加することも考えられる。これは金属２の流れを制御する別の方法を構成し、それによってダム24〜28を用いずにセル29〜34を十分に区画することもできる。また、リアクタ５にＲＨで一般に用いられる全ての装置（図示せず）を具備することができる。すなわち、オペレータが容器内の液体金属２の表面を観察するためのテレビカメラ、金属のサンプルを採取する装置（減圧処理中の金属の組成の変化をモニターするために複数の装置を容器５に沿って並べるのが有利である）、合金元素を導入する装置、酸素を吹き込む装置、容器６の耐火物を予熱するためのグラファイト抵抗体を設けることができる。酸素を吹込む装置（ランスまたは羽口）は少なくとも１つ目のセル29に設置するのが有利である。すなわち、液体金属２に溶解している酸素の初期含有率を必要に応じて増加させることによって脱炭を阻害する金属中に存在する脱酸素元素(Al,Si)を除去することができる。また、最後のセル34が液体金属２にアルミニウムを導入する手段を備えている場合には、酸素を吹込む装置の１つを最後のセル34に設置けてアルミノテルミーによって金属を最後に再加熱するのが有利である。しかし、これは最後のセル 34に入る直前の液体金属２の炭素含有率が許される場合だけである。すなわち、アルミニウムの導入で溶解している酸素はアルミナの形で捕捉され、従って、脱炭反応が最終的に停止することを意味する。また、金属２の内部に生じたアルミナが後の生産過程で除去可能であるということも意味している。変形例では、少なくとも装置19〜23のいくつかを用いて容器６の底部18に注入される流体をアルゴンではない別のガス、すなわち、最初の瞬間に液体金属中に一部溶解でき、減圧によって除去した時に脱炭が促進されるようなガスにすることができる。このガスは窒素または水素にすることができる。当然ながら、この場合は金属中のこのガスの含有率が容器のほとんどの部分においてアルゴンを吹込む通常の場合よりも高くてもそれが許容される場合である。しかし、水素は液体鋼からの除去が比較的容易な気体であるので、最後のセルまたは最後のセル全てに水素の代わりにアルゴンを注入して金属２の水素レベルを減圧リアクタの出口で通常見られるレベルにするだけでよい。窒素は液体金属からの除去速度が遅く、完全に除去されない危険がある。従って、超低炭素濃度と合わせて超低窒素濃度が要求される場合には混合ガスとして窒素を使用しない方がよい。このリアクタ５を高脱炭リアクタとしてではなく減圧脱酸素リアクタとして使用することもできる。その場合には、炭素含有率が十分に低いと見なされるレベル（例えば80ppm）に達した時に炭素を固体または気体の状態（例えばＣＨ₄の状態）で一か所または容器６に沿った複数の地点で浴中に添加し、溶解している酸素とそれとを結合させて酸素の濃度を低下させる。この脱酸素法は浴を脱酸素するために通常用いられるアルミニウムの大部分を節約できると同様に、その後に金属を鋳造する前に除去しなければならないアルミナ介在物が多量に生成するのを防ぐことができるという利点がある。従って、介在物を大幅に低下させた鋼を鋳造することができ、従って、最終製品の酸素含有率は非常に低くなる。この方法はクロムを多量に添加する前のステップとして炭素を用いた脱酸素を行うステンレス鋼の製錬にも適用できる。本発明の装置の他の利点は、通過する金属の流量がＲＨ中を流れる金属の流量に比べて非常におだやかであるという点にある(240t／分に対して10t／分)。従って、特に浸漬管の区域での耐火物の磨耗速度が大幅に低下する。本発明リアクタ５を液体金属２の連続製造ラインに挿入する代わりに、予め一定量の液体鋼を収容した（その後に液体鋼の供給がない）１つの槽から初めは空である他の槽、取鍋またはタンディッシュへ金属を移送するためにだけ使用することもできる。しかし、この場合には最終槽内の金属表面の高さが常に開始槽の金属表面の高さよりも低くなるように配置しなければならない。そのために運転中にこれらの装置をかなり複雑な方法で互いに移動させる必要が生じ、開始槽と終了槽を浅くして開始槽と終了槽の移動が大きくならないようにする。リアクタ５の入口での液体鋼の初期炭素含有率がそれほど高くない（例えば80 ppm程度）場合には、下記実施例で明らかなように、合理的な寸法の１つのリアクタで含有率を５ppmオーダーに下げることができる。初期炭素含有率が200〜30 0ppmの場合には、リアクタ５に追加のリアクタを加えることができる。この追加のリアクタは連続製造ラインでリアクタ５の上流に入れる。この追加のリアクタは炭素含有率をリアクタ５に入れるのに必要なレベル（我々の実施例では80ppm ）まで低下させる役目をする。強力なガス注入によって脱炭が補助されるならば、減圧処理で炭素含有率を200〜800ppmから80ppmへ下げる操作は極めて迅速に行われるので、完全混合セルを１つだけ有するリアクタ（従って、リアクタ５よりもはるかに短いリアクタ）を使用すれば十分である。従来型ＲＨ構造のリアクタでも浸漬チューブをそれぞれ異なる槽に浸漬したリアクタにすれば当然使用できる。以下、他の元素、例えば硫黄、窒素、酸素の含有率は当然極めて低い超低炭素含有率の鋼の連続的製造・鋳造ラインの例を説明する。この例は図２に示されている。この製造ラインは一次製錬装置40を備えている。この一次製錬装置40の役目は後の操作で組成が調節される液体金属を連続的または断続的に製造することにある。一次製錬装置40は図２に示すような従来のＬＤ転炉にすることができる。ここでは供給された液体銑鉄が脱炭によって液体鋼に変換される。脱炭は挿入ランス42を介して酸素を吹込むことで行われる。なお、他任意の一次製錬装置、例えば酸素底吹きＬＷＳ転炉、化合物吹込み型の転炉あるいはスクラップ鉄から液体鋼を製造する電気炉等も勿論好適である。液体金属２はこの一次製錬装置40から周期的に大型の製鋼取鍋43に供給される。この取鍋は緩衝槽の役目をする。取鍋 43の内容物は第１槽44へ連続注入される。この第１槽44への供給流の流速は取鍋 43に設けた公知のスライド仕切り弁（図示せず）で制御される。液体鋼２は液体金属の流れにより大気中の酸素と窒素が吸着されるのを抑制する耐火物の保護チューブ45を介して第１槽44に導入される。定常状態では、取鍋43を出る鋼の流量は例えば約10t／分であり、これは溶融装置40の平均生産速度に相当する。第１槽44では液体金属２の組成を調節するための各種操作、特に合金元素の添加と、脱硫を行うことができる。すなわち、鋼２の脱硫が必要な場合には、脱硫を減圧処理の前に行うのが好ましい。その理由の１つは脱硫操作には石灰等の水分含有率の高い材料の添加が必要になり、そうした材料は液体金属２に水素を混入させる傾向があるためである。さらに、脱硫操作では液体金属２を強力に攪拌する必要があり、それによって大気中の窒素が吸収される危険が生じる。従って、液体鋼２の脱気は、溶解ガスの含有率に対する脱硫による好ましくない影響を補償するために脱硫後に行う必要がある。さらに、脱気時の窒素の除去は液体鋼２の硫黄含有率が低いほど容易になる。第１槽44は垂直な隔壁48によって２つの区画46、47に分割され、隔壁48の下部には２つの区画間を連絡する１つまたは複数の開口49が設けるのが好ましい。第１区画47は液体鋼２が取鍋43から導入される区画であり、脱硫が行われる区画である。そのために固体物質を導入するための一般的な手段（図示せず）によって第１区画47内の治金条件を金属の脱硫にとって好ましい下記条件下に常に保つことができる： 1) 液体鋼２に溶解している酸素の含有率が非常に低い（これはアルミニウムを周期的または連続的に添加して溶解している酸素と結合させてアルミナにすることで行われる） 2) 液体鋼２の表面に石灰含有率が高く、流動性が高いスラグ50の層を存在させ、金属中の硫黄を石灰と反応させてCaＳの形でスラグ内に捕捉する（スラグは、運転を継続するに従って次第にCaＳで飽和され、脱酸素によって生じるアルミナの含有率が次第に上昇するが、スラグの組成は常に満足な状態に維持しなければならない。従って、スラグの一部を定期的に取り除くとともに石灰（場合によってはスラグの適当な流動性を保つための他の成分）を添加して除去した分を補う必要がある）。第１区画46はさらに、脱硫を行うのに必要な金属２とスラグ50との激しい攪拌を行い、アルミニウムを導入した時に生じるアルミナ介在物の大部分を除去するための液体鋼２とスラグ50との混合手段、例えばアルゴンの吹込み手段を備えている。この処理の後に得られる液体鋼２の硫黄含有率は製錬前の材料の硫黄含有率、液体鋼２上に存在するスラグ50の量および液体鋼２が第１区画46に滞留する平均滞留時間に依存する。従って、この第１区画 46の容量および形状は液体鋼２が硫黄含有率を所望値にするのに十分な平均滞留時間が保証されるように設計する必要がある。第１槽44の第２区画47に入る液体鋼２は、硫黄含有率がゼロで、第１区画46で生じたアルミナ介在物の大部分が除去された液体鋼のみである。第２区画47には大まかな脱炭を行うリアクタ53の上昇浸漬管52の下端が浸漬される。図示した実施例ではこのリアクタ53は従来型ＲＨに類似の構造を有し、２本の浸漬管すなわちアルゴン注入用の装置55を備えた上昇浸漬管52と、第１槽44とは別の中間槽57 に下端が浸漬された下降浸漬管56とを有する円筒形の容器54で構成されている。容器54はリアクタ53内を例えば50torr以下の減圧に保つための吸引装置58を備えている。液体金属２は減圧力で容器54へ吸引される。必要に応じて上昇浸漬管55 に吹込まれるガスは定常状態での第１槽44と中間槽57との間を流れる金属２の流速を第１槽44への供給速度にほぼ等しくさせる役目をする。これによって第１槽 44と中間槽57との間の金属表面の高さの差を一定に保てば、プラント全体で一定の運転条件が維持される。しかし、上昇浸漬管52にアルゴンを吹込まない場合には、金属２の脱炭を加速するために容器54自体にアルゴンを吹込む必要がある。リアクタ53の容器54の好ましくは上昇浸漬管52と一直線上に液体金属に酸素を吹込むランス59（あるいは同等の装置）を設ける。こうして導入された酸素は浴中に存在するアルミニウムを消費すると同時に鋼２に溶解して炭素と結合し、所望の大まかな脱炭が実行される。これによって金属２の炭素含有率は200〜800ppm から、例えば約80ppmにならなければならない。この含有率範囲では脱炭は非常に迅速に起こるので、この完全混合リアクタ53で十分に上記結果は達成できる。リアクタ53の出口での液体鋼２の炭素含有率は既にその当初の含有率よりもはるかに低く、液体鋼２を図１に示すようなタイプのリアクタで処理した場合に超低炭素含有率が得られるまで脱炭を継続するのに十分な量の酸素が溶解され、含有されている。次の処理は生産ラインの次のステップを構成する。すなわち液体鋼２を中間槽 57から取り出して高脱炭リアクタ５を通す。この高脱炭リアクタ５は図１に示したものと同じであるので、ここでは詳細な説明はしない。この場合には、中間槽 57が図１の中間槽４の役目をする。２つのプラントに共通な他の要素は図２では図１と同一の参照番号で表してある。最終セルまたは高脱炭リアクタ５のセルで、液体鋼２にアルミニウム、シリコンおよびマンガンなどの合金元素を連続的に添加するための手段60が加えられている。この段階では脱炭は完了しているものと見なされ、金属はアルミニウムによって溶解している残留酸素が捕捉した後に成分を最終調節する。図１のプラントと同様に、脱炭され、成分調整さられた液体鋼２は高脱炭リアクタ５の下降浸漬管10が浸漬されている連続鋳造タンディッシュ11に流入する。次いで、液体鋼２は鋳型内で凝固を開始し、スラブ、ブルームまたはビレット15 になる。このタンディッシュ11は介在物を含まないという観点から冶金的品質の高い製品を鋳造するための公知の任意の改良点、例えば金属の滞留時間を長くするための障害物、ガス吹込みまたは誘導を用いた混合装置、タンディッシュの下側に不活性ガスを吹込むための覆い等を備えているのが好ましい。これらの装置は、この実施例では金属２の最後の脱酸素がタンディッシュに入る直前に行われ、従って、この脱酸素によって生じる介在物を迅速に除去することが必要である点を考慮すれば、ここでは特に有用である。さらに、誘導またはプラズマトーチによって金属を再加熱するための周知の装置をタンディッシュ11に設けることも有利である。すなわち、液体金属２の処理中に液体金属を複数回輸送することは熱的に見てロスが大きい（特にプラントが完全に温度平衡に達していない場合）。従って、金属２の処理中の各段階で金属２を再加熱可能であれば、金属２を製錬装置40に注ぐ時に過剰に高い温度にする必要がなくなる（過剰な高温によって製錬装置の耐火物ライニングの使用期間が短くなる）。粗脱炭リアクタ53に酸素を注入することで生じるアルミニウムの燃焼作用はこの再加熱の１つである。冶金槽43、44、57に覆いと、覆いの下側に不活性ガスを吹込む手段（図示せず）とを設けて液体金属と大気との接触を制限するのが有利である。以下、例として、炭素含有率が５ppmオーダーの鋼を製造するための製造スキームを想定する： 1) 炭素含有率が約400〜800ppmの鋼を容量300tの転炉40を用いて、30分に１回の割合で（平均の生産速度は10t／分）で製錬し、金属２を取鍋43に注ぐ。 2) 流速10t／分で液体金属２を第１槽44の第１区画46へ連続的に送り、そこで脱酸素および脱硫を行う。 3) 脱酸素および脱硫された液体金属２を流速10t／分で第１槽44の第２区画47 から粗い脱炭を行うリアクタ53へ吸引し、このリアクタ53で金属２中に存在するアルミニウムの全量と炭素の一部を酸化する。リアクタ53の特性は下記の通り：容器の容量：液体金属15ｔ（これは金属２の平均滞留時間が90秒であることを意味する）圧力：50torr アルゴンの流量（上昇浸漬管52または容器54への）：60〜65ｌ／秒これらの条件で、粗い脱炭を行うリアクタ53の出口では、約80ppmの炭素と1 60ppmの溶解酸素とを含有する金属２が得られる。この金属は中間槽57へ送られる。 4) 液体金属２を中間槽57から高脱炭リアクタ５へ流速10t/分で吸引する。リアクタ５は下記の特性を有する：長さ：９ｍ幅：１ｍ金属２の平均の深さ「ｅ」：40-45cm 作業圧力：50torr以下セルの数：９（上昇浸漬管８が開口した１つ目のセル２９を含む）(脱酸素元素（アルミニウム、シリコンなど）および他の合金元素が添加される場合には、これらのセルの最後のセルは成分調整専用のもので、脱炭には関与しない) １つ目のセル29の長さ： 1.8ｍ他のセルの長さ： 0.9ｍ各セルでのアルゴンの流量：約15ｌ／秒各セルでの金属の平均滞留時間：15秒（１つ目のセル29を除く、１つ目のセル29の平均滞留時間は30秒であり、従ってリアクタ中での合計の滞留時間は150秒）１つ目のセルでの炭素含有率：30ppm ８番目および９番目のセルでの炭素含有率：５ppm ・脱炭、脱酸素されて成分に変化を付けられた液体金属２を、タンディッシュ11へと導入する； 5) 金属２を、鋳型13に注いで冶金製品15を作る。上記実施例では、同じ生産速度を有する従来のＲＨと比較して、大まかに脱炭を行うリアクタ53と、本発明のリアクタ５とでの金属２の滞留時間を合わせると金属の一部が減圧に曝されて脱炭される時間を８倍にすることができることが分かる。製錬装置40の出口での窒素含有率が高過ぎず、それに続く段階（特に１つの容器から別の容器への金属の移送および混合）で窒素が取り込まれることがないえらば、超低炭素含有率と超低窒素濃度(30ppm以下)とが対になって得られる。窒素含有率をさらに低くすることが望まれる場合には上記の操作モードは最適ではない。その理由は、高度に脱炭された金属は溶解酸素の含有率が高いために、最終のセルで行われる脱窒素はごくわずかになるためである。従って、脱炭によって生じるＣＯを用いた掃気では小さ過ぎ、溶解酸素が脱窒素の反応速度に与える好ましくない影響を相殺することはできない。従って、高脱炭リアクタ５の１つ目のセルへのアルゴンの流量を増加させ、さらに／または、アルゴンの代わりに水素を用いて脱炭の反応速度を加速して従来の方法よりも早く目的とする炭素含有率を得ることができ、次に、脱酸素用のアルミニウムを最後のセルでなくさらに上流で添加する。従って、最後のセル内で脱酸素された金属に大量のガス（アルゴンまたは水素）を吹き込むとによって、最後のセルを脱窒素専用とすることができる。また、既に述べたように、リアクタ５を高脱炭リアクタでなく炭素を用いた金属の減圧脱酸素を行うためのリアクタとして使用することができる。そうすることの利点は、液体金属の最終的な脱酸素のために最低量のアルミニウムが必要であり、最終的に、内包される酸素含有率の非常に低い金属が得られる点にある。そのためるは上記製造スキームで粗脱炭リアクタ53によって得られる炭素含有率80ppm（例えば）は許容可能である。本発明のリアクタ５ではアルゴン注入の代わりに液体または気体の炭化水素、例えばメタン、ＣＨ₄を注入することもできる。この炭化水素はクラッキングによって炭素と水素とに分解する。炭素は金属２に溶解している酸素と結合してＣＯを構成する。その生成反応速度は水素によって加速される。各セルで注入する炭化水素の量を変えて脱酸素の進行中、浴の炭素含有率が一定となるようにすることもできる。すなわち、溶解酸素の含有率を約10ppmにすると同時に最初の炭素含有率80ppmを保持することもできる。また、超低炭素含有率(5ppm)と超低酸素含有率(10ppm)とを同時に達成することも考えられる。そのためには、リアクタ内の圧力を10torr以下に低下させて所定の炭素含有率でバランスする熱力学的平衡で酸素の含有率を低下させる必要がある。上記の製造ラインの変形例として、一次製錬装置40および取鍋43の代わりに、連続的運転される一次製錬装置を用いることが考えられる。この装置はプラント内の液体金属の流速にほぼ等しい流速で液体金属を直接第１槽44に連続的に注入する。本発明は上記実施例に限定されるものではなく、変更をして本発明の冶金リアクタおよびそれを用いた液体鋼製造プロセスにすることができる。必須の点はリアクタのデザインを決定する一般原則、すなわち理想的なブラグフローの場合にできるだけ近いリアクタ内での液体金属の流れを保持しなければならないということである。本発明のリアクタはカスケート状に使用することができる。同様に、上記リアクタは特に炭素含有率が低いわけではないが、介在物をほとんど含有せず、しかも溶解ガスの含有量を低くすることが望まれる鋼の製造にも何ら問題なく使用可能であるということは明らかである。本発明は鋼以外の金属の製造にも適用できることは明らかである。The present invention relates to the smelting of liquid steel, in particular with a very low carbon content, of course nitrogen and The present invention relates to the smelting of high-purity steel with a low oxygen content. In the present smelting of liquid metal, it is general to use a vacuum reactor of a type called “RH”. This reactor is equipped with the following 1) and 2): 1) A deep cylindrical container with a refractory lining on the inside (the upper part of which is capable of depressurizing the inside of the container to at least 1 torr during operation of the reactor) 2) Two pipes or dip tubes with a cylindrical or elliptical cross section lined with refractory inside and outside, one end open at the bottom of the container and one The dip tube is equipped with a device for blowing gas (usually argon gas). This reactor is used as follows. That is, the ladle containing the liquid metal to be treated is carried under the RH and the lower end of the dip tube is immersed in the ladle. Then, the inside of the container is depressurized. This sucks up a certain amount of metal in the container. Finally, the gas injection into one dipping tube is started. The function of this blowing is to move the metal in the dip tube towards the container. Therefore, this dip tube is referred to as a "climbing dip tube". The metal that has passed through the container then descends again into the ladle via the other dip tube, called the "descent dip tube". Thus, the metal continuously circulates between the ladle and the container. During the processing time (generally 10 to 30 minutes), the metal droplets stay in the container multiple times. The average residence time is determined by the flow velocity of the metal in the dip tube and the capacity ratio between the ladle and the container. In principle, by moving liquid metal into a container under reduced pressure, the content ratio of hydrogen dissolved in liquid metal and nitrogen dissolved in liquid metal (which cannot be lowered as much as hydrogen) is reduced. You can Other metallurgical operations that take place in the vessel include: 1) oxygen previously dissolved in the metal or oxygen and carbon intentionally blown through a lance or tuyere inserted into the wall of the vessel. Partial decarburization to combine, 2) Addition of alloying elements in a state shielded from air and ladle slag, i.e. with optimum efficiency, 3) Reheating of metal with aluminothermy (adding aluminum to metal and then adding oxygen Reheating due to oxidation of aluminum by blowing) The metal in the ladle is gently stirred as the metal circulates between the ladle and the container. This is convenient for precipitating non-metallic inclusions. In the steel industry, the demand for iron products with extremely low carbon content (50 ppm or less), especially cold rolled sheets with excellent ductility and tensile strength, deep drawing steel and chrome-molybdenum ferritic stainless steel is increasing. ing. The most suitable in-ladle metallurgical reactor for producing such steels on an industrial scale has proved to be RH. In fact, the rate of decarburization in the reactor is improved by injecting a large amount of gas into the ascending dip tube or into the vessel. In other words, in the case of a ladle containing 300t of liquid steel, if the RH container with a capacity of 15t is used, the flow rate is 240t / min, and the reaction time is 10 minutes, the carbon content of the steel will decrease from 300ppm to 20ppm. Can be made. Since the demand for high-purity steel is ever increasing, steel with a lower carbon content (5-10 ppm) is normally produced at a productivity at least equivalent to that of the current equipment (about 10 t / min at a large general factory). What can be done will be required in the very near future. However, in the current RH, the decarburization reaction rate obviously decreases when the average carbon content in the liquid steel becomes 30 ppm or less. Increasing the reaction rate can achieve the desired metallurgical performance in a time corresponding to the optimum operating conditions of other steelmaking equipment, but in order to do so, the flow rate of metal and the amount of gas blown in must be greatly increased. However, if this is done, the refractory wears out in a short time, so that the plant operation must be stopped more frequently, and the reliability of the plant operation decreases. Briefly, it is considered impossible to achieve a carbon content of substantially 10 ppm or less at an industrial rate under technically and economically sufficient conditions in a conventional RH. In any case, it is important to keep the carbon content in the liquid steel as low as possible. In fact, steel is often carburized in subsequent manufacturing and casting processes (eg, in contact with tundish, mold refractory, surface coating powder, etc.). It is an object of the present invention to provide a novel metallurgical reactor for bringing the carbon content in liquid steel close to 10 ppm or less under conditions of sufficient production efficiency. The reactor of the present invention can also be used to produce steel with a low degree of decarburization but a very low content of oxidizing inclusions. The object of the present invention is to suck liquid metal from a starting tank into a reactor whose pressure is reduced with respect to the starting tank, to flow the metal in the reactor under conditions close to a plug flow, to metallize the metal, and to pass through the reactor. A method for adjusting the composition of a liquid metal is characterized in that the metal is discharged to a final tank, and the reactor is depressurized for this final tank as well. It is preferable to continuously supply the metal to the starting tank and to continuously discharge the metal from the final tank. In one embodiment of the method of the present invention, the liquid metal is steel, the metallurgical treatment comprises decarburization, denitrification or vacuum deoxygenation with carbon and the final bath is a tundish for continuous casting. Another object of the invention is to have a starter tank containing the liquid metal, a reactor and an end tank, the reactor comprising a container, the interior of which is to the pressure in the starter tank and the end tank. A means for maintaining a decompressed state, a first dipping pipe called an ascending dipping pipe, one end of which is immersed in a liquid metal housed in a starting tank and the other end of which is connected to the bottom of the container, and one end of which is a final tank. A second dipping pipe, which is dipped in the liquid metal housed in, and the other end of which is connected to the bottom of the container, called a descending dipping pipe, and the liquid metal is started through each dipping pipe and the reactor container. And a means for continuously flowing the liquid metal between the final tank and the final tank, and the container is shaped so as to flow the liquid metal in a state close to a plug type flow when the liquid metal moves between the dipping tubes. It is a facility for adjusting the composition of liquid metals such as steel characterized by The equipment of the present invention is incorporated into a plant for controlling the composition of liquid steel, including: 1) a primary smelter for liquid steel, 2) deoxidation of liquid steel from a primary smelter into liquid metal. Means for continuously pouring into the first tank provided with means for introducing the agent and mixing means, 3) means for depressurizing the inside, and first dipping immersed in the liquid metal contained in the first tank) Reactor for roughly decarburizing liquid metal, including a container having a tube and a second immersion tube immersed in an intermediate tank, 4) means for blowing oxygen into the liquid metal provided in the container 5) Means for continuously flowing liquid metal between the first tank and the intermediate tank, 6) Equipment for adjusting the composition of at least one of the above liquid metals (the intermediate tank constitutes the starting tank in this equipment) ). As can be seen from the following description, the novel reactor of the present invention has something in common with RH. That is, there is a decompression container and two dipping pipes, and the metal enters the container through each dipping pipe and exits from the container. However, the principle of continuously circulating liquid metal between the ladle and the reactor is not adopted. That is, in the present invention, the metal leaving the reactor is poured into a tank other than the starting tank and does not return to the same reactor. Furthermore, while RH behaves completely as a mixing reactor, the liquid steel in the reactor of the present invention must have a flow close to a plug flow. As will be apparent from the description below, by dividing the reactor into a plurality of fully mixed cells as needed, a pseudo plug flow is obtained and mass exchange between each cell is minimized. The reactor of the present invention is advantageously incorporated in a continuous or semi-continuous liquid steel production line. The invention will be understood more clearly from the following description with reference to the accompanying drawings. FIG. 1 is a conceptual longitudinal sectional view of an embodiment of the metallurgical reactor of the present invention. FIG. 2 is a conceptual longitudinal cross-sectional view of an embodiment of an entire ultra-low carbon steel production / casting line in which the reactor of the present invention is incorporated. One of the reasons why ultra-high degree decarburization cannot be performed sufficiently quickly in RH is that a predetermined unit portion of the liquid metal is exposed to reduced pressure for a relatively short averaging time. In the example above, with a liquid metal capacity of 15t combined with a 300t ladle and a flow rate of 240t / min RH, the average residence time for some metal to remain in the RH container is 10 minutes. On the other hand, it is only 30 seconds. Most of this 30 seconds is taken in the first stage of the relatively easy decarburization to change the carbon content from 200 to 400ppm to 30ppm, after which other steelmaking equipment (converter, electric furnace, There is not enough time left to decarburize below the 10 ppm level at a production rate comparable to that of continuous casting). Furthermore, since the principle is to continuously recirculate the metal between the ladle and the container, the metal supplied to the container always has a decarburization degree higher than that of the metal already in the container and undergoing decarburization. Low. Since the vessel operates as a fully mixed reactor, the average carbon content C of the metals in the vessel at any instant _V And the average carbon content C of the metal in the ladle _L Can be defined as C _L Is always C _V Is greater than the carbon content C _L With a low decarburization metal influx _V It can be seen that the decrease of This is C for expressing the efficiency of reaction rate. _V / C _L It can be well represented by a mathematical model of decarburization including the ratio. C for faster decarburization _V / C _L The ratio should be as close to 1 as possible. In conventional RH this value is on average around 0.6 and is a function of the progress of decarburization and the recirculation rate of the metal. This C _V / C _L The condition (1) is ideally satisfied when all the metals to be treated are simultaneously exposed to the reduced pressure, which corresponds to the case where the pressure in the ladle is reduced by the conventional equipment. However, when such equipment is used, the gas is added to the whole metal, so one of the basic advantages of RH is to pass a large amount of gas through the metal to accelerate the decarburization reaction rate. The advantage of doing is lost. That is, if such a large amount of gas is simply passed through a depressurized ladle, excessive splashes of metal are generated and the equipment is extremely rapidly damaged. The use of a reduced pressure ladle also eliminates another advantage of RH: the metal surface exposed to reduced pressure is larger than the volume contained in the vessel. Therefore, decarburization cannot be performed sufficiently quickly as a whole with a ladle that is simply decompressed or a decompression furnace-ladle, and therefore it cannot be industrially used to reduce the carbon content to 40 ppm or less. C _V / C _L Another approach to approaching the ideal conditions of is to change the shape of the dip tube and the flow rate of the gas blown into the rising dip tube to increase the circulation speed of the metal between the ladle and the vessel. , Then, the wear of the refractory will be significantly accelerated. FIG. 1 is a conceptual diagram of the principle of a unit reactor of the present invention and an embodiment when it is incorporated in a steel continuous production facility. This steel manufacturing facility is provided with a supply gutter 1 of liquid steel 2 continuously flowing at a controllable flow rate from a metallurgical vessel (not shown) such as a steel ladle, a converter, or a primary smelting facility similar to an electric furnace. I have it. The primary smelting equipment is also operated continuously. The supply gutter 1 is connected to a cover 3, the cover 3 is supported by an intermediate tank 4 under atmospheric pressure, and the liquid steel 2 flows into this intermediate tank 4. An inert gas, eg argon, is preferably injected inside the supply trough 1 and under the cover 3 to protect the metal 2 from the air. From the liquid steel 2, it is desirable to remove as much gas (hydrogen and nitrogen) and carbon dissolved therein as possible. For that purpose, the metallurgical reactor 5 of the present invention is used. Like the conventional RH reactor, the reactor 5 of the present invention is also lined with refractory inside and is equipped with: 1) to contain a certain amount of liquid steel 2 flowing in at a certain moment. Container 6 (This container 6 must have a sufficiently high upper portion so as not to be excessively damaged by the splash of liquid metal like the RH container) 2) Gas suction for depressurizing the inside of the container 6 Device 7 3) Ascending dip tube 8 penetrating cover 3 and immersed in intermediate tank 4 (providing means 9 for flowing liquid metal 2 through container 6 and for injecting a gas such as argon to assist the flow) 4) A descending dip tube 10 through which the liquid metal emerging from the container 6 passes. In the present invention, unlike the RH, the descending dip tube 10 discharges the liquid metal to the finishing bath 11 rather than returning it to the same bath as the up dip pipe 8. In the illustrated embodiment, the finishing tank 11 is a tundish for continuous casting equipment. This tundish 11 optionally comprises at least one outlet nozzle 12, through which the liquid metal 2 is forced on the inside of the wall at a flow rate controllable by a stopper rod or slide valve not shown. Continuously flowing into the cooled bottomless mold 13, the steel skin 14 begins to solidify inside the mold 13, and this skin is a metallurgical product such as slab, bloom or billet depending on the shape and size of the mold 13. Become 15. The RH container has a substantially cylindrical shape, and its inner diameter is up to several meters. Due to this structure, the RH has the characteristics of a completely mixed reactor. On the other hand, the container 6 of the present invention must be a reactor 5 having characteristics as close as possible to a plug flow type reactor. In a plug-flow reactor, steel that has been degassed and / or decarburized to a certain level does not mix with less pure steel. One solution to do so is to make the interior of the container 6 duct-like, with an elongated passageway of rectangular or substantially rectangular cross-section, at the end of which the dip tubes 8, 10 are connected. The ratio between the distance between the dip tubes 8 and 10 and the width of the passage should be at least 6. For example, the width of the container 6 can be 1 to 1.5 m and the distance between the dip tubes 8 and 10 can be 8 to 10 m. The decarburization / degassing efficiency largely depends on the ratio of the surface area of the liquid metal 2 exposed to the reduced pressure to the volume of the liquid metal 2 in the container 5. This ratio should be as high as possible. That is, for the same volume, the depth "e" of the metal in the container 5 should not be too deep (e.g. 0.40-0.80 m). This depth depends on the structure of the entire plant (in particular, the difference in height between the container 6 and the intermediate tank 4 and the tundish 11), the pressure applied to the surface 16 of the liquid steel 2 inside the container 6 and the intermediate tank 4 and the tundish. It is governed by the pressure exerted on the surface 17 of the liquid steel 2 inside 11, the pressure difference ΔP between it and the atmospheric pressure. Let Δh be the average difference in height between the surface of the liquid steel 2 in the reactor vessel 6 and the surfaces 16 and 17 exposed to atmospheric pressure, Δh = ΔP / ρ · g [ρ is the liquid Steel density (approximately 7,000 kg / m ^Three ), G is the acceleration of gravity (9.8 m / s ² )] Becomes. Therefore, Δh (m) ≈ 1.46 · 10 ^-Five ΔP (Pa) Assuming that the absolute pressure in the container 6 is P and the pressure of 1 atm (101 325 Pa) is applied to the intermediate tank 4 and the tundish 11, Δh ≈ 1.46 ・ 10 ^-Five (101325-P) Therefore, when P is 50 torr, Δh≈1.40 m, and when P is 1 torr, Δh≈1.50 m. Therefore, the depth e of the liquid metal 2 in the container 5 is relatively independent of the level of decompression obtained in the container 5 in the normal pressure range. As mentioned above, the metal flow from the tanks 4 to 11 through the reactor 5 is dominated by this gas injection, if a gas is injected at the ascending dip tube 8. However, in any case, the existence of this flow and the accompanying flow rate of the metal depend on the height difference between the surface 16 of the liquid metal 2 in the intermediate tank 4 and the surface 17 of the liquid metal 2 in the tundish 11. To do. This height difference is particularly related to the difference between the feed flow rate to the intermediate tank 4 and the flow rate of metal 2 exiting the tundish 11. It is preferable that the shape of the container 6 of the reactor 5 is a duct so that the liquid metal 2 can perform a plug type flow. However, due to the supply of metal from the ascending dip tube 8, the release of the argon gas injected into the ascending dip tube 8 if necessary, and the decarburization of the metal (at least this decarburization occurs most intensively). There is a risk that vigorous agitation will occur (in the upstream region of the vessel 6 in which it is present), which will lead to uncontrollable loss of flow conditions. Therefore, it is desirable to divide the vessel 6 of the reactor 5 into a series of complete mixing cells and limit the exchange of liquid metal 2 between the cells as much as possible to obtain a flow close to a plug flow. For that purpose, a device 19-23 for injecting a fluid such as argon can be provided at the bottom 18 of the container 6. This pouring device is similar to, for example, the permeable member or tuyere used in steelmaking converters, electric furnaces and ladles. These injection devices 19 to 23 serve to vigorously stir the liquid metal 2 in the respective areas in which they are installed. If the injection devices 19 to 23 are separated from each other by a sufficient distance, the affected areas are sufficiently separated from each other so that the liquid metal 2 does not move from one cell to another. It is considered that the cell will not diffuse back to the cell immediately before it. Therefore, a uniform carbon concentration is obtained in each cell, which is constant over time (as long as the other operating conditions are constant), which makes this situation the ideal decarburizing condition expected by the mathematical model. Equivalent to. Also, the injection rate of argon significantly accelerates the decarburization reaction rate. As shown in FIG. 1, optimization can be performed by providing dams 24 to 28 in the container 6 and physically separating each cell. Each dam 24-28 is arranged at right angles to the main direction of the container 6 to define each cell 29 to 34, and each cell is provided with a fluid injection device 19 to 23 (gas is injected into the ascending dip tube 8). In the case of the first cell 29, the metal of the first cell 29 can be removed by excluding the first cell 29 which is agitated by pouring into the ascending dip tube 8). The first dam (the dam separating the first cell 29 and the second cell 30) 24 extends from the bottom 18 of the container 6 and the upper part thereof overflows when the liquid metal 2 flows into the container 6. It is preferable to have a height such that the sill 35 that can be moved is obtained. With this configuration, the flow rate of the flowing metal 2 can be accurately controlled. The other dams 25-28 are provided with openings 36-39 to allow the liquid metal 2 to travel within the container 6 while ensuring a minimal passage between each cell 30-34. Each opening 36-39 is preferably formed at the bottom of the dam 25-28 to allow the container 6 to be completely drained. In this way, the areas affected by the fluid injection devices 19 to 23 are sufficiently limited, the risk of excessive metal exchange between two adjacent cells is eliminated, and a large number of fluid injection devices can be installed. become. Therefore, the condition of the ideal plug flow can be approached as compared with the case without the dam. Instead of a gas injection device, it is also conceivable to use or add a device for stirring the metal 2 using a moving electromagnetic field oriented in a suitable direction. This constitutes another way of controlling the flow of metal 2 and also allows the cells 29-34 to be well compartmentalized without the use of dams 24-28. In addition, the reactor 5 can be equipped with all the devices (not shown) commonly used in RH. That is, a television camera for the operator to observe the surface of the liquid metal 2 in the container, a device for taking a sample of the metal (a plurality of devices are installed along the container 5 to monitor the change in the composition of the metal during the depressurization process). Can be provided), a device for introducing alloying elements, a device for blowing oxygen, and a graphite resistor for preheating the refractory material of the container 6 can be provided. The oxygen blowing device (lance or tuyere) is advantageously installed in at least the first cell 29. That is, by increasing the initial content rate of oxygen dissolved in the liquid metal 2 as necessary, the deoxidizing elements (Al, Si) existing in the metal that inhibit decarburization can be removed. Also, if the last cell 34 is equipped with means for introducing aluminum into the liquid metal 2, one of the oxygen blowing devices should be installed in the last cell 34 and the metal finally reheated by aluminothermy. Is advantageous. However, this is only the case when the carbon content of the liquid metal 2 just before entering the last cell 34 is allowed. That is, it means that the oxygen dissolved by the introduction of aluminum is trapped in the form of alumina, and thus the decarburization reaction is finally stopped. It also means that the alumina generated inside the metal 2 can be removed in the later production process. In a variant, the fluid injected into the bottom 18 of the container 6 using at least some of the devices 19-23 can be partially dissolved in another gas which is not argon, ie liquid metal at the first moment, It is possible to use a gas that promotes decarburization when removed. This gas can be nitrogen or hydrogen. Of course, in this case it is acceptable if the content of this gas in the metal is higher than the usual case of blowing argon in most parts of the container. However, since hydrogen is a gas that is relatively easy to remove from liquid steel, argon is injected into the last cell or all of the last cells instead of hydrogen, and the hydrogen level of metal 2 is normally seen at the outlet of the vacuum reactor. All you have to do is reach the required level. Nitrogen has a slow removal rate from liquid metal, and there is a risk that it will not be completely removed. Therefore, when ultra-low nitrogen concentration is required together with ultra-low carbon concentration, it is better not to use nitrogen as a mixed gas. The reactor 5 can also be used as a reduced pressure deoxygenation reactor instead of as a high decarburization reactor. In that case, when the carbon content reaches a level considered to be sufficiently low (eg 80 ppm), the carbon is in a solid or gaseous state (eg CH 2 _Four State), it is added to the bath at one point or at a plurality of points along the container 6 to combine dissolved oxygen with the dissolved oxygen to reduce the concentration of oxygen. This deoxygenation method saves most of the aluminum normally used to deoxygenate the bath, as well as prevents the formation of large amounts of alumina inclusions that must subsequently be removed before casting the metal. There is an advantage that you can. Therefore, steel with significantly reduced inclusions can be cast, and thus the final product has a very low oxygen content. This method can also be applied to the smelting of stainless steel in which deoxidation using carbon is performed as a step before adding a large amount of chromium. Another advantage of the device according to the invention is that the flow rate of the metal passing through is very gentle compared to the flow rate of the metal flowing in the RH (240 t / min vs. 10 t / min). Therefore, the wear rate of the refractory material is significantly reduced, especially in the area of the dip tube. Instead of inserting the inventive reactor 5 into a continuous production line for liquid metal 2, from one tank initially containing a certain amount of liquid steel (no subsequent supply of liquid steel) to another tank which is initially empty, It can also only be used to transfer metal to a ladle or tundish. However, in this case, the height of the metal surface in the final tank must always be lower than the height of the metal surface in the starting tank. This requires that these devices be moved relative to each other during operation in a fairly complex manner, making the start and end vessels shallow so that the start and end vessels do not move significantly. When the initial carbon content of the liquid steel at the inlet of the reactor 5 is not so high (for example, about 80 ppm), as will be apparent from the following examples, one reactor having a reasonable size has a content of the order of 5 ppm. Can be lowered to Additional reactors can be added to reactor 5 if the initial carbon content is between 200 and 300 ppm. This additional reactor is placed upstream of reactor 5 in a continuous production line. This additional reactor serves to reduce the carbon content to the level required to enter reactor 5 (80 ppm in our example). If decarburization is assisted by strong gas injection, the operation of reducing the carbon content from 200-800ppm to 80ppm by the depressurization process is extremely rapid, so a reactor having only one complete mixing cell (and therefore a reactor) It is sufficient to use a reactor (much shorter than 5). Even a conventional RH structure reactor can be naturally used if the dip tubes are immersed in different tanks. An example of a continuous production / casting line of steel having an ultra-low carbon content, which naturally has a very low content of other elements such as sulfur, nitrogen and oxygen, will be described below. An example of this is shown in FIG. This production line is equipped with a primary smelting device 40. The role of the primary smelting apparatus 40 is to continuously or intermittently produce a liquid metal whose composition is adjusted in a later operation. The primary smelting device 40 can be a conventional LD converter as shown in FIG. Here, the supplied liquid pig iron is converted to liquid steel by decarburization. Decarburization is performed by blowing oxygen through the insertion lance 42. Of course, any other primary smelting apparatus such as an oxygen bottom blown LWS converter, a compound blown converter or an electric furnace for producing liquid steel from scrap iron is also suitable. The liquid metal 2 is periodically supplied from the primary smelting device 40 to a large steel ladle 43. This ladle acts as a buffer tank. The contents of the ladle 43 are continuously poured into the first tank 44. The flow velocity of the supply flow to the first tank 44 is controlled by a known slide gate valve (not shown) provided in the ladle 43. The liquid steel 2 is introduced into the first tank 44 through a refractory protective tube 45 that suppresses adsorption of oxygen and nitrogen in the atmosphere by the flow of liquid metal. In steady state, the flow rate of steel exiting the ladle 43 is for example about 10 t / min, which corresponds to the average production rate of the melting device 40. In the first tank 44, various operations for adjusting the composition of the liquid metal 2, particularly addition of alloying elements and desulfurization can be performed. That is, when desulfurization of the steel 2 is required, it is preferable to perform desulfurization before the depressurization treatment. One of the reasons is that the desulfurization operation requires the addition of a material having a high water content, such as lime, and such material tends to mix hydrogen into the liquid metal 2. Furthermore, the desulfurization operation requires vigorous agitation of the liquid metal 2, which poses a risk of absorbing atmospheric nitrogen. Therefore, the degassing of the liquid steel 2 must be performed after desulfurization in order to compensate for the undesired effects of desulfurization on the content of dissolved gas. Furthermore, the removal of nitrogen during deaeration becomes easier as the sulfur content of the liquid steel 2 is lower. The first tank 44 is preferably divided into two compartments 46, 47 by a vertical partition 48, and the bottom of the partition 48 is preferably provided with one or more openings 49 communicating between the two compartments. The first section 47 is a section in which the liquid steel 2 is introduced from the ladle 43, and is a section in which desulfurization is performed. To that end, the metallurgical conditions in the first compartment 47 can always be kept under the following conditions, which are favorable for the desulfurization of metals, by the usual means for introducing solid substances (not shown): 1) to the liquid steel 2 Very low content of dissolved oxygen (this is done by adding aluminum periodically or continuously to combine with dissolved oxygen to form alumina) 2) Surface of liquid steel 2 A layer of slag 50 with high lime content and high fluidity is present, and sulfur in the metal reacts with lime and is trapped in the slag in the form of CaS (slag gradually becomes CaS as the operation continues). Saturated and deoxidized, the content of alumina gradually increases, but the composition of the slag must always be kept to a satisfactory level, so some slag should be removed regularly and lime (in some cases) It is necessary to compensate for the amount that was removed by the addition of other components) to keep the proper fluidity of the slag). The first section 46 further includes the liquid steel 2 and the slag 50 for vigorous stirring of the metal 2 and the slag 50 required for desulfurization to remove most of the alumina inclusions generated when aluminum is introduced. Is provided with a mixing means such as argon blowing means. The sulfur content of the liquid steel 2 obtained after this treatment is the sulfur content of the material before smelting, the amount of slag 50 present on the liquid steel 2 and the average residence time of the liquid steel 2 in the first section 46. Depends on. Therefore, the volume and shape of this first compartment 46 must be designed so that the liquid steel 2 is guaranteed an average residence time sufficient to bring the sulfur content to the desired value. The liquid steel 2 entering the second section 47 of the first tank 44 is only liquid steel having a sulfur content of zero and having the majority of the alumina inclusions produced in the first section 46 removed. In the second section 47, the lower end of the ascending dip pipe 52 of the reactor 53 for roughly decarburizing is dipped. In the illustrated embodiment, this reactor 53 has a structure similar to that of a conventional RH, and is intermediate between the two dip tubes, ie, the rising dip tube 52 with a device 55 for argon injection, and the first tank 44. It is composed of a cylindrical container 54 having a descending immersion pipe 56 whose lower end is immersed in a tank 57. The container 54 is equipped with a suction device 58 for keeping the inside of the reactor 53 at a reduced pressure of, for example, 50 torr or less. The liquid metal 2 is sucked into the container 54 by the depressurizing force. The gas blown into the ascending dip pipe 55 as necessary serves to make the flow velocity of the metal 2 flowing between the first tank 44 and the intermediate tank 57 in the steady state substantially equal to the supply speed to the first tank 44. To do. As a result, if the difference in height of the metal surface between the first tank 44 and the intermediate tank 57 is kept constant, constant operating conditions are maintained in the entire plant. However, if argon is not blown into the ascending dip tube 52, it is necessary to blow argon into the container 54 itself in order to accelerate the decarburization of the metal 2. A vessel 54 of the reactor 53 is preferably provided with a lance 59 (or equivalent device) for blowing oxygen into the liquid metal in line with the riser dip tube 52. The oxygen introduced in this way consumes the aluminum present in the bath and at the same time dissolves in the steel 2 and combines with the carbon to carry out the desired rough decarburization. This should lead to a carbon content of metal 2 of 200 to 800 ppm, for example about 80 ppm. Since decarburization occurs very quickly in this content range, the above-mentioned result can be sufficiently achieved in this complete mixing reactor 53. The carbon content of the liquid steel 2 at the outlet of the reactor 53 is already much lower than its original content, and when the liquid steel 2 is treated in a reactor of the type shown in FIG. Sufficient oxygen is dissolved and contained to continue decarburization until obtained. The next process constitutes the next step in the production line. That is, the liquid steel 2 is taken out from the intermediate tank 57 and passed through the high decarburization reactor 5. The high decarburization reactor 5 is the same as that shown in FIG. 1 and will not be described in detail here. In this case, the intermediate tank 57 functions as the intermediate tank 4 of FIG. Other elements common to the two plants are represented in FIG. 2 by the same reference numbers as in FIG. In the final cell or the cell of the high decarburization reactor 5, means 60 for continuously adding alloying elements such as aluminum, silicon and manganese to the liquid steel 2 is added. At this stage decarburization is considered complete and the metal finalizes the composition after the residual oxygen dissolved by the aluminum has been scavenged. Similar to the plant shown in FIG. 1, the decarburized liquid steel 2 whose composition has been adjusted and flows into the continuous casting tundish 11 in which the descending dip pipe 10 of the high decarburization reactor 5 is immersed. The liquid steel 2 then begins to solidify in the mold into a slab, bloom or billet 15. This tundish 11 has any known improvements for casting metallurgical quality products in terms of inclusion-free inclusions, such as obstacles, gas blowing or induction to increase the residence time of the metal. It is preferable that the mixing device used, a cover for blowing an inert gas under the tundish, and the like are provided. Considering that these devices are carried out in this example just before the last deoxidation of metal 2 enters the tundish, it is therefore necessary to quickly remove the inclusions produced by this deoxidation. , Here is particularly useful. Furthermore, it is also advantageous to provide the tundish 11 with well known devices for reheating the metal by induction or plasma torches. That is, transporting the liquid metal a plurality of times during the treatment of the liquid metal 2 causes a large loss in terms of heat (especially when the plant is not completely in temperature equilibrium). Therefore, if the metal 2 can be reheated at each stage during the treatment of the metal 2, it is not necessary to raise the temperature too high when pouring the metal 2 into the smelting device 40 (the refractory of the smelting device is refractory due to excessive high temperature). The usage period of the material lining is shortened). One of the reheating processes is the burning action of aluminum that occurs when oxygen is injected into the crude decarburization reactor 53. Advantageously, a cover is provided on the metallurgical bath 43, 44, 57 and means (not shown) for blowing an inert gas under the cover to limit the contact between the liquid metal and the atmosphere. As an example, assume a manufacturing scheme for manufacturing a steel having a carbon content of 5 ppm order: 1) A steel having a carbon content of about 400 to 800 ppm is converted into a steel in a converter 40 having a capacity of 300 tons in 30 minutes. Smelting is performed once (average production rate is 10 t / min), and the metal 2 is poured into the ladle 43. 2) The liquid metal 2 is continuously fed to the first section 46 of the first tank 44 at a flow rate of 10 t / min, where deoxidation and desulfurization are performed. 3) The deoxidized and desulfurized liquid metal 2 is sucked at a flow rate of 10 t / min from the second compartment 47 of the first tank 44 into the reactor 53 which performs coarse decarburization, and in this reactor 53 the aluminum present in the metal 2 is removed. It oxidizes all and part of carbon. The characteristics of the reactor 53 are as follows: Volume of the vessel: 15 t of liquid metal (which means that the average residence time of metal 2 is 90 seconds) Pressure: 50 torr Argon flow rate (into the ascending dip tube 52 or vessel 54) ): 60-65 l / sec. Under these conditions, at the outlet of the reactor 53 for coarse decarburization, a metal 2 containing about 80 ppm of carbon and 160 ppm of dissolved oxygen is obtained. This metal is sent to the intermediate tank 57. 4) The liquid metal 2 is sucked into the high decarburization reactor 5 from the intermediate tank 57 at a flow rate of 10 t / min. Reactor 5 has the following characteristics: Length: 9 m Width: 1 m Average depth of metal 2 "e": 40-45 cm Working pressure: 50 torr or less Number of cells: 9 (one with rising dip tube 8 open If deoxidizing elements (aluminum, silicon, etc.) and other alloying elements are added (including the eye cell 29), the last of these cells is dedicated to composition adjustment and decarburization. Length of first cell 29: 1.8 m Length of other cells: 0.9 m Argon flow rate in each cell: approx. 15 l / sec Average residence time of metal in each cell: 15 sec (Excluding the first cell 29, the average residence time of the first cell 29 is 30 seconds, so the total residence time in the reactor is 150 seconds.) Carbon content in the first cell : 30ppm Carbon content in the 8th and 9th cells: 5ppm ・ Liquid gold whose composition has been changed by decarburization and deoxygenation 2, is introduced into the tundish 11; 5) a metal 2, making metallurgical product 15 is poured into the mold 13. In the above-mentioned embodiment, as compared with the conventional RH having the same production rate, when the residence time of the metal 2 in the reactor 53 for roughly decarburizing and the reactor 5 of the present invention is adjusted, a part of the metal is decompressed. It can be seen that the time to be decarburized by exposure to can be increased eight times. Very low carbon content, if the nitrogen content at the outlet of the smelter 40 is not too high and nitrogen is not taken up in subsequent steps (especially the transfer and mixing of metal from one vessel to another) The rate and ultra-low nitrogen concentration (less than 30ppm) are obtained as a pair. The above modes of operation are not optimal when a lower nitrogen content is desired. The reason is that the highly decarburized metal has a high content of dissolved oxygen, so that the denitrification performed in the final cell is negligible. Therefore, scavenging with CO produced by decarburization is too small to offset the unfavorable effect of dissolved oxygen on the denitrification kinetics. Therefore, by increasing the flow rate of argon to the first cell of the high decarburization reactor 5 and / or by using hydrogen instead of argon to accelerate the reaction rate of decarburization, the purpose of the present invention is faster than the conventional method. The carbon content can be obtained and then aluminum for deoxidation is added further upstream than in the last cell. Therefore, by blowing a large amount of gas (argon or hydrogen) on the deoxidized metal in the last cell, the last cell can be dedicated to denitrification. Further, as described above, the reactor 5 can be used not as a high decarburization reactor but as a reactor for performing depressurization deoxidation of a metal using carbon. The advantage of doing so is that a minimum amount of aluminum is required for the final deoxygenation of the liquid metal, which ultimately results in a metal with a very low oxygen content. Therefore, the carbon content of 80 ppm (for example) obtained by the crude decarburization reactor 53 in the above manufacturing scheme is acceptable. In the reactor 5 of the present invention, instead of argon injection, liquid or gaseous hydrocarbons such as methane, CH _Four Can also be injected. This hydrocarbon decomposes into carbon and hydrogen by cracking. Carbon combines with oxygen dissolved in metal 2 to form CO. The production reaction rate is accelerated by hydrogen. It is also possible to change the amount of hydrocarbons injected in each cell so that the carbon content of the bath remains constant during the progress of deoxidation. That is, the dissolved carbon content can be set to about 10 ppm and the initial carbon content of 80 ppm can be maintained. It is also conceivable to achieve an ultra low carbon content (5 ppm) and an ultra low oxygen content (10 ppm) at the same time. For that purpose, it is necessary to reduce the pressure in the reactor to 10 torr or less and reduce the oxygen content rate by thermodynamic equilibrium in which a predetermined carbon content rate is balanced. As a modified example of the above production line, it is conceivable to use a continuously operated primary smelting device instead of the primary smelting device 40 and the ladle 43. This device continuously injects liquid metal directly into the first tank 44 at a flow rate approximately equal to the flow rate of liquid metal in the plant. The present invention is not limited to the above embodiments, and can be modified to the metallurgical reactor of the present invention and the liquid steel manufacturing process using the same. The essential point is that the general principle that determines the design of the reactor is that the liquid metal flow in the reactor must be kept as close as possible for the ideal Bragg flow. The reactor of the present invention can be used in a cascading manner. Similarly, the reactor is not particularly low in carbon content, but can be used without problems in the production of steel that contains almost no inclusions and is desired to have a low dissolved gas content. That is clear. Obviously, the invention can be applied to the production of metals other than steel.

───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.⁶ 識別記号庁内整理番号ＦＩＣ２１Ｃ 7/10 9264−4ＫＣ２１Ｃ 7/10 Ｓ (72)発明者ロス，ジャン−リュクフランス国 57070 メッツリュドュロワ―アルベール 30─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI C21C 7/10 9264-4K C21C 7/10 S (72) Inventor Ross, Jean-Luc France 57070 Met's Rudeux Lower Albert 30

Claims

[Claims] 1. Liquid metal is sucked from the starting tank into the reactor which is depressurized with respect to this starting tank, Flow metal in the reactor under conditions similar to plug flow, metallize the metal, and The metal that has passed through the reactor is discharged to the final tank, and the reactor is also depressurized to this final tank. A method for controlling the composition of a liquid metal, which comprises: 2. Claim to continuously supply metal to the starting tank and to continuously discharge metal from the final tank The method according to Item 1. 3. The method according to claim 2, wherein the final tank is a tundish for continuous casting. 4. The reactor is divided into a plurality of cells, each cell forming a complete mixing region. The method according to any one of 1 to 3. 5. The liquid metal is steel, and the metallurgical treatment comprises decarburization. The described method. 6. The liquid metal is steel and the metallurgical treatment comprises denitrification. The method described in. 7. The liquid metal is steel and the metallurgical process comprises vacuum deoxygenation with carbon. 6. The method according to any one of 6. 8. Start tank (4) containing liquid metal, reactor (5), and end With a tank (11), the reactor (5) comprises a container (6), which starts its interior A means (7) for maintaining a reduced pressure state with respect to the pressure in the tank (4) and the end tank (11) and one end It is immersed in the liquid metal (2) contained in the starting tank (4), and the other end is placed on the bottom (18) of the container (6). The first immersion pipe (8) called the connected ascending immersion pipe and one end is housed in the final tank (11) Dipped in liquid metal (2), with the other end connected to the bottom (18) of the container A second immersion pipe (10) called a pipe, and a liquid metal of each immersion pipe (8, 10) and reactor (5) A means for continuously flowing between the starting tank (4) and the final tank (11) via the container (6) is provided. The container (6) plugs the liquid metal as it moves between each dip tube (8,10). Steel, etc. characterized by having a shape that flows in a state close to the type flow Equipment for adjusting the composition of the liquid metal (2) of. 9. The cross section of the container (6) is almost rectangular, the distance between each dip tube (8, 10) and the width of the container (6) The installation according to claim 8, having a ratio of at least 6. Ten. The container (6) stirs the liquid metal (2) and transforms the container (6) into multiple complete mixing cells (29-34). 10. Equipment according to claim 8 or 9 having a plurality of means for dividing. 11. The agitation means comprises means (19-23) for injecting a fluid into the liquid metal. Facility. 12． The installation according to claim 11, wherein the fluid of at least a part of the stirring means is argon. 13. The equipment according to claim 11, wherein at least a part of the fluid of the stirring means is hydrogen. 14. The equipment according to claim 11, wherein at least a part of the fluid of the stirring means is a hydrocarbon. 15． Stirring means comprising means for applying a moving electromagnetic field to the liquid metal (2). The equipment according to any one of the items. 16. Each cell (29-34) separated by a dam (24-28), each dam separated by it Equipment according to any one of claims 10 to 15 having holes to allow communication between cells. . 17． A means for continuously flowing the liquid metal between the starting tank (4) and the final tank (11) is a rising dip tube ( A method according to any one of claims 8 to 16 including means (9) for blowing gas into the liquid metal (2) in 8). Equipment described in. 18． A means for continuously supplying liquid metal (2) to the starting tank (4) and liquid gold from the final tank (11). A means (12) for continuously extracting the genus (2). Equipment. 19. The equipment according to claim 18, wherein the final tank (11) is a tundish for continuous casting. 20. Equipment for adjusting the composition of liquid steel, including: 1) Primary smelting equipment (40) for liquid steel (2), 2) Deoxidation of liquid steel (2) from the primary smelter (40) into liquid metal (2) Means (4) for continuously pouring into the first tank (44) equipped with a means for introducing a base material and a mixing means (51) 3), 3) Immersing in the liquid metal (2) housed in the first tank (44) and the means (58) for decompressing the inside The first immersion pipe (52) and the second immersion pipe (56) immersed in the intermediate tank (57). Reactor (53) for roughly decarburizing the liquid metal (2), including a container (54) for 4) A means (59) for blowing oxygen into the liquid metal provided in the container (53), 5) A means for continuously flowing the liquid metal (2) between the first tank (44) and the intermediate tank (57), 6) Equipment for controlling the composition of at least one liquid metal according to claims 8-19. (The intermediate tank (57) constitutes the starting tank (4) in this equipment). twenty one. The primary smelting device (40) itself has means (43) for continuously pouring the liquid steel (2) into the first tank (44). 21. The equipment of claim 20 which comprises. twenty two. The first tank (44) divides this tank into two compartments (46, 47) communicating with each other (48) ), And one compartment (46) from the means (43) for injecting liquid metal into the first tank (44) It receives the liquid metal (2) and the oxygen scavenger coming in, and the crude decarburization reactor ( Installation according to claim 20 or 21, wherein the first immersion tube (52) of 53) is immersed. twenty three. A means for continuously flowing the liquid metal (2) between the first tank (44) and the intermediate tank (7) is a first means. 23. Any of claims 20 to 22 including means (55) for blowing gas into the liquid metal in the dip tube (52). The equipment described in paragraph 1.